Generally, a vertical axis wind power generator utilizes a plurality of vanes to intercept the flow of air currents and according the wind force, so as to drive a main shaft of the wind power generator to rotate for generating electric power. For the purpose of intercepting a large amount of air currents, the vanes of the vertical axis wind power generator usually have a considerably large area and a length as long as 10 to 15 meters. However, it is very troublesome and time-consuming to manufacturing vanes with so large area and length. Also, it is very inconvenient to install and maintain or repair these large vanes.
A vertical axis wind power generator has a vertical main shaft, on which a plurality of vanes are mounted to space from one another along a circumferential surface of the main shaft. Each of the vanes has a front side and a rear side that are generally two corresponding outward curved face and inward curved face, respectively. The inward curved face of the vane is located against the wind to intercept the flow of air currents and accordingly the wind force, so that the vane is push by the wind to thereby drive the main shaft to rotate. Then, the rotating force of the main shaft is transmitted to a plurality of power generator sets for generating electric power.
Since the vanes of the vertical axis wind power generator are sequentially circumferentially spaced around the main shaft, the inward curved rear face of a preceding vane is oriented toward the outward curved front face of a following vane. When the wind blows against the inward curved rear face of one vane, it also blows against the outward curved front face of another diametrically opposite vane. That is, only the wind blowing to the inward curved rear face of the vane is useful to effectively rotate the main shaft, while the wind blowing to the outward curved front face of the vane simply forms a resistance to the rotation of the main shaft.
It is noted the vanes for the conventional vertical axis wind power generator all are a complete plate without any opening formed thereon. When the wind blows to the outward curved front face of the vane, the outward curved front face functions to guide the wind to outer sides of the vane to thereby reduce the air resistance thereto. Nevertheless, the relatively large area of the vane would still block the wind to thereby reduce the overall push produced by the wind against the inward curved rear faces of other vanes. Since the wind force capable of driving the main shaft to rotate is reduced, the effect of wind power generation is disadvantageously reduced accordingly.